1. Field of the Invention
This invention relates generally to machines for dispensing carbonated beverages, and is concerned in particular with a dual function dispensing head which insures a constant and fixed flow of each liquid component to the machine's diffusion and dispensing nozzle, coupled with on/off adjustment.
2. Description of the Prior Art
Conventional dispensing heads typically employ spring-loaded ceramic valves to control the flow of syrups and carbonated water to nozzles which serve to combine and dispense the liquids. The ceramic valves include mating sliding surfaces that are sensitive to variations in input pressures, liquid viscosities and sticky sugar syrups, resulting in non-uniform mix ratios and an uneven quality of the dispensed beverages. There are also much more expensive volumetric dispensing valves that electronically measure the flow rate of the carbonated water and then meter the syrup. These also suffer accuracy due to the variations in input pressures and viscosity.
In an attempt at alleviating this problem the conventional dispensing heads include means for manually adjusting flow rates to compensate for changing input pressures and viscosities. However, this entails constant attention and frequent recalibrations, and can lead to other problems, including accidental as well as intentional watering down of beverages by unscrupulous merchants.